Fox number one. So,
that is me, locked in a pen in San Diego.
And that is a very special red fox from Russia.
We’re testing whether the fox likes me,
because it’s actually bred to be friendly towards people. And,
in that moment, I’m really hoping it passes the test.
I’m just minding my own business.
Exotic pets are weirdly compelling,
especially on social media.
They’re like a glimpse into this alternate reality
where we domesticated raccoons instead of cats and dogs. But,
they’re not really domesticated.
Animals like cats, dogs, horses, pigs,
猫 狗 马 猪等等这些动物
we bred them for generation after generation
to live alongside humans.
Exotic pets are hand raised, but they’re basically still wild animals
with maybe one exception.
We drove up into the hills outside San Diego
to meet a very few rare animals.
They’re foxes that are born without any built-in fear or aggression towards humans.
They wag their tails at you; they like treats.
They’re very curious about you, though they are a little camera shy.
There’s nothing quite like them. Aww,
I got a lick, I got a lick.
噢 它舔我 它在舔我
We’re visiting Amy and David Bassett at their Canid Education and Conservation Center.
It’s sort of an interactive zoo built
to introduce the general public to foxes.
The Bassetts got them as pets, but not from an exotic pet breeder.
They’re the result of a nearly 60-year long Russian science experiment. Victor,
sit, sit, good fox
维克多 坐下 坐下 乖狐狸
It all traces back to a Soviet geneticist
named Dmitry Belyaev
In the 1950s, Belyaev hit on an idea
that was radical for its time, that domesticated animals like dogs
are friendly to people because of genes
that govern their behavior. Meaning,
the process that turned wolves into dogs
tens of thousands of years ago was essentially evolution.
There were friendliness genes that won out in wolves
as they adapted to live alongside humans.
These foxes exist because of the way
Belyaev tested his idea.
In 1959, his team began selectively breeding foxes
at the Institute of Cytology and Genetics
in remote Novosibirsk, Russia.
The criterion was simple.
The foxes that showed the least fear or aggression
when approached by experimenters were allowed to breed.
The less friendly foxes weren’t.
They selected the next generation of foxes the same way,
and the next generation, and the next, for decades.
Belyaev died in 1985,
but the work continued and by 2004
nearly 70% of the foxes had reached
an elite level of friendliness.
By some measures, they had domesticated the fox,
which is how a few years back
two dog lovers found themselves in over their heads.
We had absolutely no idea.
They’re very cheeky, very mischievous, get into everything,
它们极其鲁莽 极其顽皮 到处乱钻
chew and tear everything apart.
David and Amy currently own five
of the only 10 or 15 Belyaev foxes
in the United States.
They cost around $9,000 to buy and import one
all the way from Siberia and they came with a learning curve.
We learned quickly that they are not really house trained. So,
they will poop and pee everywhere. So,
it’s not very easy to have them
in your kitchen, say, when they jump on the counters and poop.
The Bassetts have since
adjusted to life with foxes,
but they’ve learned that being domesticated is one thing,
being man’s best friend is another.
While they are certainly tame, they’re fascinating and incredible animals,
they’re still foxes and when you domesticate a fox,
you don’t make a dog, you make a domesticated fox.
Anymore than when you domesticate a horse you make a dog.
So, Belyaev did not
recreate the dog, but for anyone studying
how wolves evolved into dogs,
the foxes might still represent a behavioral stepping stone.
They’re on a path to doghood, if you like.
Clive Wynne is professor of psychology
at Arizona State.
He studies the unique relationship between dogs and people
and the way that dogs go above and beyond simple friendliness towards humans.
Dogs have this emotional availability.
I something call it hyper-sociability that
they are so very, very ready and willing to form emotional relationship.
Accord to Clive, at least 14,000 years ago
hyper-social dogs emerged from a population of wild wolves
and no one’s really sure how it happened.
I mean, that is the million-dollar question, and we don’t exactly know.
But, the Belyaev foxes
might offer a clue.
Clive and his team have a simple test
to see how far along the foxes are
on their path to doghood.
And they told us how to carry it out. So,
the experiment is really simple.
I have a one-meter radius circle
all the way around me and they’re gonna bring
in a fox one at a time
into this enclosure.
The idea was to see how much of two minutes
the foxes would spend inside my circle.
We tried first with the three
and one-by-one they trotted up, sniffed me,
and then relaxed somewhere else,
which has been Clive’s experience with the foxes, too.
they greet, and they interact, and then they move on
它们打了个招呼 感知彼此 就走开了
For comparison, we also tested a fox
that was hand-reared by humans, but genetically wild.
It never set foot inside the radius
and it never relaxed. And,
for a final contrast, we tested a dog.
I gotta ignore you for two minutes. Afterwards,
we got to spend some more time
with the Belyaev foxes
and they were completely tame with us,
just not so friendly.
Clive and the Bassetts suspect that this is
because of their early lives as lab animals.
They were bred for generations to be friendly,
but then barely socialized as youngsters,
and that’s important, too.
The fact that I am such a nice guy
isn’t just the beautiful genes that I inherited from my parents,
but the experiences of life that I’ve had along the way.
Clive and his team plan to keep studying fox
behavior to build out a roadmap for how dogs became dogs. But,
locked inside each of those foxes is another roadmap,
one that might help explain domestication in any animal.
In some situation, it’s like a single gene.
In some situation, it’s still few genes.
Anna Kukekova is a professor of animal sciences
at the University of Illinois at Urbana-Champaign.
Since 2002, she’s been collaborating with the institute
in Russia on genetics research.
Her goal is to reach the absolute core
of the fox experiment, the specific genes involved in fox domestication.
And a few weeks ago,
she and her team published a paper
in Nature, Ecology, and Evolution that made a lot of progress.
Now we know that there are about hundred regions in fox genome
which in some way can contribute to some behaviors,
so tame behavior, friendly behavior, or aggressive behavior.
Anna’s research is valuable,
because it directly compares the genes
of wild and domesticated foxes.
We can do that with wolves and dogs,
but we can’t infer as much about it.
As dogs evolved, friendliness just wasn’t
the only trait that mattered.
For example, they also had to digest human food. So,
we can see which genes changed from wolves to dogs,
but it’s harder to know whether those really are behavior genes.
On the other hand, there was only one fox trait
that Belyaev selected for, friendliness towards humans. So,
here it’s a little easier to associate behavior with DNA.
Can we actually nail down some regions to a single gene
and try to demonstrate that this gene actually has affected behavior?
And we were successful.
This is such a big deal,
because there’s a lot of overlap in mammalian genes. So,
these genes that Anna found,
they could help us understand domestication across the board. And,
given that, it’s possible that we could use
gene editing tools to domesticate
entirely new animals in the lab, maybe.
Yeah, we were thinking about that.
You know, I have doubts that we ever will be able
to create a mouse which wags its tail.
I don’t think it will work.
But, we’ll see.
But, back in reality,
where does that leave the foxes?
They’re still being bred for the experiment,
but they’re also trickling out into the world as pets,
which puts them in a strange no-man’s land
between a wild animal and a companion.
They were not created the same way dogs were
and they’re certainly not dogs now. But,
if you know to look for it,
there’s a hint of something familiar about them.
You take the short moments when they’re scared
they’ll come to you.
If you’re open to it and you realize what that means.
What’s the significance of this semi-wild animal
who just came to you for comfort and that’s kind
of what you have to understand
in order to bond with a fox.
It’s these small moments that have
huge significance to them.
So, one thing we didn’t talk about
was that even though Belyaev
only selected for friendliness, there were a lot
of physical changes to the foxes, too.
Their coats were different, their ears got floppier,
even their skulls changed.
It’s called domestication syndrome and you should read about it,
because it is wild.
Fox number one. So,